5 mins read

Overview: Permethrin is applied to the skin as a cream or lotion. It is used to treat certain conditions caused by tiny insects, such as scabies and head lice. The most common side effect is a burning, stinging, irritated, or itchy feeling on the skin where it is applied. Before using this medicine, tell your healthcare provider if you are allergic to ragweed.

Uses

What is permethrin used for?

Permethrin is commonly used for the following conditions caused by tiny insects.

Permethrin may also be used for other conditions as determined by your healthcare provider.

How does permethrin work (mechanism of action)?

Permethrin kills tiny insects, such as head lice and mites, by disrupting their nerves and muscles. 

How is permethrin supplied (dosage forms)?

Brands and other names

  • Acticin
  • Elimite
  • Nix

Dosage forms and strengths

  • 5% topical cream
  • 1% topical lotion

How should I store permethrin?

Topical Cream. Permethrin cream should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Topical Lotion. Permethrin lotion should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). Store in a cool, dry place.

Side Effects

What are the most common side effects of permethrin?

The most common side effects of permethrin are burning, stinging, itching, or irritation where it is applied. Tell your healthcare provider if you have any of these side effects that bother you.

There may be other side effects of permethrin that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of permethrin?

While less common, the most serious side effects of permethrin are described below, along with what to do if they happen.

Severe Allergic Reactions. Permethrin may cause allergic reactions, which can be serious. Stop using permethrin and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use permethrin?

Allergies to Ingredients. People who are allergic to any of the following should not use permethrin.

  • Acticin
  • Elimite
  • Nix
  • Permethrin
  • Any other medicine known as a pyrethroid or pyrethrin
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific permethrin products they stock.

What should I know about permethrin before using it?

Do not use permethrin unless it has been prescribed to you by a healthcare provider. Use it as prescribed.

Do not share permethrin with other people, even if they have the same condition as you. It may harm them.

Keep permethrin out of the reach of children. If your child requires treatment with permethrin, you or another caregiver should apply the medicine and wash it off for them as directed by your healthcare provider.

Permethrin should only be applied to the skin and hair. Do not get the medicine in your mouth, eyes, eyelashes, eyebrows, ears, nose, lips, or vagina. If the medicine gets into the eyes, gently flush your eyes with water. Wash your hands thoroughly after use. 

The instructions for applying permethrin may change depending on which condition you are treating. When this medicine is used to treat head lice, it comes in a bottle and should be shaken well before use. When this medicine is used to treat scabies, it comes in a tube. Talk to your pharmacist or other healthcare provider if you are uncertain how to apply permethrin.

Once you have used permethrin, it is important to take other steps to stop the mites or lice. For example, all exposed bedding, clothing, hats, and towels should be washed in hot water or dry cleaned. Any exposed personal care items, such as brushes, combs, or hair clips, should be washed in hot water.

If you are using permethrin to treat head lice, you should check for lice about one week after using this medicine. If you find live lice, speak with your healthcare provider about whether you or your child may need a second treatment. 

If you are using permethrin to treat scabies, you may still have symptoms of scabies, such as itching, for one to two weeks after treatment. If you still see live mites two weeks after using this medicine, speak with your healthcare provider about whether you or your child may need a second treatment.

What should I tell my healthcare provider before using permethrin?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if permethrin is right for you.

In particular, make sure that you discuss any of the following.

Ragweed Allergy. Tell your healthcare provider if you have an allergy to ragweed.

Pregnancy. It is not known if or how permethrin could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.

Breastfeeding. It is not known if permethrin passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does permethrin interact with foods or drinks?

There are no known interactions between permethrin and foods or drinks.

It is unknown if drinking alcohol will affect permethrin.

Does permethrin interact with other medicines (drug interactions)?

There are no known interactions between permethrin and other medicines. Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much permethrin?

If you or someone else has used too much permethrin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of permethrin?

Permethrin is meant to be applied one time, when needed. Use it as your healthcare provider recommends. Do not apply extra doses.